The present invention relates to an image recognition method, an image recognition device and an image recognition program, and particularly relates to an image recognition method, an image recognition device and an image recognition program which can be suitably used for search for a target image.
An image recognition technique for searching a taken image for a target object at a high speed has been in the spotlight. With ADAS (Advanced Driving Assistant System), for example, a pedestrian, another vehicle, etc. are recognized from an image taken by a camera provided on a motor vehicle. For such recognition, a image region of interest is selected from a taken image, and feature quantity data calculated from image data of the region are compared with dictionary data, which are feature quantity data previously calculated concerning an image searched for, thereby evaluating a degree of matching. HOG (Histogram of Oriented Gradients) has been known as an algorithm for extracting feature quantities in such time. In HOG, an image is divided into blocks; a brightness gradient direction and a concentration gradient are calculated to create a histogram.